Currently, the surgeon typically enters a complex spine operation having prepared only by looking at the patient's preoperative imaging studies (x-ray, CT, and MRI). The objective of this project is to develop a computerized system to assist the spine surgeon in better planning and executing complex surgery. The system will first enable the surgeon to perform virtual spine surgery on a patient-specific computer model of the spine. The system will then suggest possible refinements to the surgery with regard to hardware placement. Next, the system will create rapid prototyped solid models of the spine that the surgeon can take into consultation with the patient and into surgery for better visualization of anatomy. Finally, the system will create rapid prototyped templates and drill guides for intraoperative use to allow the surgeon to implement the surgical plan. The first two years of the project involve development of the tool and the final year involves laboratory and clinical experimental validation of the tool. The ultimate goal of the computerized tool is to improve the outcome of surgery, shorten the time under anesthesia, and improve the confidence of the patient and surgeon. Thus, successful development of the surgical planning tool would represent an improvement in the quality of care in spine surgery.